ICAR Technical Series no. 7 - Nitra Proc.

Effect of two milking systems on teatMaterials andmethodsAutumn calving Friesian type dairy cows (n = 56), were assigned postcalving to two milking treatments. Treatment 1 consisted of a heavy clusterweight (3.20 -kg) with a claw volume of 150 ml, wide bore tapered liners(31.6 mm –21.0 mm) and used simultaneous pulsation. Treatment 2consisted of a light cluster weight (1.65 -kg) with a claw volume of 275 ml,narrow–bore liners (25.0 mm – 20.0 mm) and alternate pulsation. Cowswere milked in a 14-unit swing-over side by side milking parlour, withthe milk elevated into a 60 mm milk-line 1.4 m above the cow standing.The clusters were removed automatically when the milk-flow rate droppedto 0.2 -kg/min. The AM and PM milking interval was 18 and 6 hrsrespectively. Teats were washed with running water and dried with papertowels before cluster application. Milk production (kg), milking timekg/min and peak milk flow-rate was recorded daily. A Chlorohexidineteat disinfectant was applied post milking to right-sided teats and leftsidedteats were left untreated.Teathyperkeratosis,teat texture andcolourTeats were scored for hyperkeratosis (TH) using five classifications scores(0=normal, 1=slightly raised smooth or broken ring, 2=moderate raisedsmooth or broken ring, 3=large smooth or broken ring, 4=extreme brokenring). Teat classification was carried out monthly after PM milking by theauthor using a miner’s headlamp and a personal organiser to store data.Machine milking can cause short-term changes in teat hardness and colour.Teats generally have a pink colour after milking, but some teats becomereddened or blue. One operator unfamiliar with the milking treatments,classified teat barrels for teat texture by manual palpation and teat colourby visual assessment. The teats were scored for texture as soft, firm orrough. All cows teats were examined twice on consecutive days duringmid lactation, and teats were classified within one minute of clusterremoval. Statistical analyses were done using a Kruskal-Wallis one wayanalysis of variance test to compare teat scores between treatments. Teatscore comparisons were also made for front and hind teats using theWilcoxon matched pairs test.Results anddiscussionThere was no significant difference in TH scores for the two treatments ateach month of classification or over the complete lactation (Figure1).TH increased with stage of lactation and was higher for front teats ascompared to rear teats. TH was significantly higher for right-sided teatsas compared to left-sided teats. An increased prevalence of TH has beenreported to occur in dairy cattle during winter months particularly duringcold weather (Timms, et al., 1997). Weather changes during the autumn/winter-milking period and wet teats due to teat-dip application, mayexplain the higher TH scores recorded with right-sided teats. Thepercentage of teats classified as soft, firm or rough and with pink or redcolour are presented in table 1. The number of pink and reddened teats ispresented as a percentage of light coloured teats. There was no difference244Conference on "Physiological and technicalaspects of machine milking"